Buyer Beware of Home DNA Tests

No sooner does a scientific discovery make it possible to feed the desire to control our destiny than a new industry springs up to cash in on it.

Thus, deciphering of the human genome and identification of specific genetic markers for various heritable diseases and traits has spawned dozens of companies that sell genetic tests directly to consumers, mostly over the Internet.

As a source of entertainment at so-called spit parties or an effort to trace genetic ancestry, the tests might be seen as relatively harmless (unless someone is appalled to discover who their ancestors might be). But for the many people who are bypassing the medical profession to determine, they believe, how likely they are to develop a life-threatening disorder, experts say direct-to-consumer genetic testing is fraught with potential dangers.

Hope and Hype

Not the least of these hazards is false reassurance over a feared risk, prompting someone to throw caution to the winds. A woman told she lacks a mutation that makes breast cancer likely might forgo regular mammograms, even though she still faces the average one-in-eight lifetime risk of developing the disease.

Or a man told he lacks genes linked to an elevated risk of heart disease might decide to smoke, eat lots of salt and saturated fats, avoid exercise or develop a large paunch, any of which could overcome his supposed genetic protection.

“It’s important to separate hope from hype,” Dr. Jennifer House, president of the March of Dimes, said at a recent meeting of its national communications advisory council. “Direct-to-consumer genetic testing is a buyer-beware market. Consumers need to be very, very cautious.”

She said that in addition to a possible waste of money — the cost of genetic testing ranges from about $300 to $3,000, depending on the extent of the analysis — there is serious concern about the quality of information consumers receive from testing companies.

No federal law provides oversight of these companies and their tests. The Food and Drug Administration and the Federal Trade Commission exercise little if any authority over the accuracy and reliability of the tests and how they are advertised and sold. No drug agency approval is needed if there is no test kit to buy and the company does its own lab work.

Although California and New York have sent “cease and desist” orders to many genetic testing companies, saying they need licenses to solicit specimens of DNA from state residents, most companies have found ways around the restrictions. They might harvest DNA in other states and hire in-house doctors to approve the analyses as valid medical tests.

The result is that while it is illegal, for example, to spit into a test-tube for direct-to-consumer DNA testing in New York, you can go to New Jersey to spit and have the sample analyzed in New York.

Are the Tests Reliable?

At the March of Dimes meeting in June, Dr. Siobhan Dolan, an expert in human genetics at Sarah Lawrence College, said there were four criteria for assessing the value of a genetic test: analytic validity, or whether the test accurately and reliably measures what it purports to assess; clinical validity, whether the test is able to detect risk of disease; clinical utility, whether there is something that can be done to alter a detected risk; and ethical validity, whether the test or its use violates social, legal or moral precepts, like conferring a stigma or leading to discrimination.

At the moment, the reliability of most gene tests on all four criteria is questionable, Dr. Dolan said, adding that the “broad landscape of direct-to-consumer genetic testing is a slippery slope.”

In a 2006 report in Ethics & Medicine, Katherine Wasson of the National Cancer Institute and her co-authors argued that “the potential harms outweigh the potential benefits of such tests.” They explained that many genes have varying degrees of penetrance, meaning that the probability that they would be expressed in a given individual is unpredictable and can be influenced by environmental and lifestyle factors.

“Even if a person has a genetic mutation associated with a particular disease or condition, this does not necessarily predict when it will develop, if at all, or its severity,” they wrote.

They added that most screening tests vary in their ability to correctly identify who will and who will not have a particular condition, and “currently, this information is not available for many direct-to-consumer genetic tests.”

In a “Facts for Consumers” bulletin issued in 2006, the Federal Trade Commission noted that “having a particular gene doesn’t necessarily mean that a disease will develop; not having a particular gene doesn’t necessarily mean that the disease will not.”

Another critical point is that several, and perhaps many, different genes can influence a person’s risk of developing various diseases, including heart disease and cancer. Many of those genes have yet to be identified, so finding that you lack a harmful gene already known, like a gene linked to Alzheimer’s disease, may not mean you will be spared that disease.

Keep in mind, too, that of the more than 20,000 genes in the human body, only a small number are examined in direct-to-consumer genetic tests. There are now more than 1,100 genetic tests clinically available and several hundred more being studied in research settings. That leaves a lot of genes that can make a health difference that cannot now be tested.

For the moment, regardless of what a genetic test might show, the best course is to follow the usual recommendations about adopting healthful living habits and avoiding exposure to noxious substances.

Expert Advice Needed

Interpretations of tests results offered by some companies fall way short of what a consumer might learn from a certified medical geneticist or genetic counselor. Those who choose to go the direct route to genetic tests would be wise to take the findings to a qualified expert. The American College of Medical Genetics advises both a pretest and post-test consultation, based partly on personal and family medical history.

Complicating matters is a relative shortage of genetic counselors to clarify the significance of test results, and the fact that most practicing physicians lack the knowledge and training in genetics to interpret them properly. That often leaves consumers to jump to their own, often erroneous, conclusions about the meaning of their gene test findings.

Privacy concerns are another important issue. Consumers have no way to know how a company might use their genetic material.

“Your DNA might be sold, shared or used without your consent for testing and research,” Lori B. Andrews, a professor at the Chicago-Kent College of Law, told the March of Dimes meeting. “Some companies are just a front end for biotech companies that use it for research. Only 11 states require a company to obtain consent before they test someone’s DNA.”